a joint investigation by abc news and the food and environment reporting network found more than 100 reported illnesses due to blue-green algae exposure. >> essentially if we don't solve this problem somebody is going to die. >> reporter: ohio state's dr. jeffrey reuter is the foremost authority on blue-green algae and he says it is a nationwide problem caused by farm fertilizer runoff. the cure he says is convincing farmers to carefully fertilize so nutrients stay on the fields and not in the water. >> other wise the blooms are going to continue to grow, the human health problems that we see are going to increase. >> reporter: assaulting our senses, our economy, and our health. jim avila, abc news, wisconsin. >> that is nasty stuff. >> the wisconsin department of natural resources says the best way to treat this is naturally. but, they say that it could take several years to get rid of it come fleetl completely, a large amount of lake erie, third of the surface covered. >> cut big time into the fishing industry there. in more or less every state. peaks august through september. near